Massive bone allografts allow us to treat easily large osseous defects. This study reports our experience with 90 massive allografts of whom 50 had more than 2 years follow-up. The reconstruction was in half of cases the femur, in ten patients one or more vertebra, hemipelvis in five, humerus in four and tibia in three cases. The main indication was tumor surgery: 30 malignant, 6 benigns, but also for the treatment of massive bone loss in ten prothesis replacement and in 4 miscellaneous pathology (malformation, infection ...). The massive allografts allow us more anatomic reconstructions and particularly in young patients we can observe some rehabitation of the graft by host cells. The complication rate is quite high mainly mechanical (10 fractures) in the first two years following surgery, but also 2 sepsis and 2 sciatic palsy. Simultaneously an experimental and morphological study of cartilaginous fragments was undertaken: at first, we define the best method of fixation and examination of human articular cartilaginous fragments by electronic microscopy. This method was then applied to cartilaginous fragments liable to various cryoprotective solutions, stocked for various periods at different temperature and subjects to programmed cryocongelation. So we are able to define the best conditions of cryoconservation of human adult articular cartilage fragments and we can observe that 70-80% of cells maintain normal morphological structure suggesting a perfect cellular viability.